On October 1, 1945, I stood at the hypocenter of the Hiroshima atomic bombing and made a slow revolution. In that instant I had a difficulty grasping that this city had been felled by a single explosion. Nothing in my experience had prepared me to conceive of that magnitude of destructive force.

Working as an army engineer for three years, I had dealt with explosive materials on a daily basis, and I thought I knew their power. Standing there, I simply could not accept at an emotional level that a single bomb had done all this.